Depending on the size of the pipe, it can mean an unpleasant sight for your basement. However, identifying the pipes largely depends on the age of your house and the material that the pipeline was made from since it gives you a clue to its purpose.
What Are the Mysterious Pipes in The Basement Floor?
One of the last places to be completed when building a new house is the basement floor slab. That’s because there are different embedded plumbing pipes and weeping tile and often a sump pit that should be completed before pouring the concrete. In addition, the plumbing drain pipes are usually interconnected beneath the slab and might have various vertical sections protruding through the finished concrete. The different possibilities about the mystery pipes in your basement floor include:
Drains
In older homes, you might see a cast-iron section of the draining piping, which in some instances is cut off flush with the floor or slightly embedded in the concrete floor slab.
If your house were built in the last 30 years, you’d probably see black ABS drains. These vertical drains will have a small diagonal section sticking out of the basement floor and a threaded cover. They allow access to the drain pipes interior after the floor is poured.
If your house is less than 15 years old, you may have the ABS drains but an inner backwater valve installed with a straight vertical section and often a cap. Typically, it’s flush with the basement floor slab top. If the cap is removed, you can see a shallow void with minimal or no water at the bottom.
Newer homes can also have roughed in plumbing drains on the basement floor for a future bathroom. The toilet drain pipe is typically installed with a short segment sticking through the floor slab, high enough for a cap to be installed. If the cap is removed and the pipe cut flush with the basement floor, you’ll see a void pipe with no water at the bottom and no odor coming out of it.
An Eavestrough Drain
In older homes, mystery pipes on the basement floor could be an abandoned Eavestrough drain. Years ago, eavestrough downspouts used to drain through the exterior walls or foundation to empty into a short stack sticking some feet out of the basement floor slab.
The eavestrough vertical pipes are often connected under the slab to the catch basin that drains the water into the floor drain. However, the practice was discontinued since it often resulted in overburdened sewers and basement backups during the heavy rainfalls.
Standpipe
The pipes could be the standpipes, which are open-ended pipes that are screwed into the basement floor to permit water flow back up. This will delay or prevent basement floods. The standpipes are a throwback to the mid-20th century when drain systems couldn’t handle the stormwater. They are usually 21/2 to 4 inches wide and can rise several feet above the basement floor.
Natural Gas Line
If the pipe has a diameter of ¾ inch, it’s most likely a natural gas line. You can turn off the gas and remove the cap to smell for gas. Alternatively, have someone turn the gas on and off while the lid is off, and you can easily confirm whether it’s a gas line.
Cistern Or Municipal Water Supply
If the pipe is 1.5 inches sticking up straight from the floor about 2.5 feet tall, it could be an abandoned cistern. The pipeline typically has no smell, and the course could be threaded. If your home area has a municipal water supply, the mysterious pipe could be an old water supply line. However, if the pipe is on the side of the home furthest from the street, it could be a non-municipal service.
What Can Be PVC Pipes in My Basement Floor?
Typically, you’ll see two PVC radon pipes in older homes because there’s sand or dirt under the basement slab. However, in new construction, one pipe is deemed enough since there’s gravel under the slab, and air can move more freely.
What Are 4-Inch Mystery Pipes in the Basement Floor?
The 4-inch mysterious pipes in the basement could be a cleanout for the main drain line. It’s often there for regular cleaning or emergencies. It’s used when a significant clog is blocking the main sewer line.
The cap can be removed, and with a motorized auger, the pipe can be used to unclog the main drain. That’s necessary, especially if the specialists have trouble clearing the blockage or your house plumbing experiences frequent problems.
Typically, removing the clean pipe will leave the buried drain open to the basement without a trap at the bottom. That allows sewer gas to enter the basement, unrestricted by water in a trap, and could be a health hazard. It can also give an unpleasant smell to the area surrounding the open drain. If you detect an odor at the top of the pipe, you’ll know it’s a backwater or cleanout valve.
Essential Note: If the pipe is 2-inch, it could be for a shower or tub, while 3-inch is for the toilet.
Why Do Old Homes Have Small Galvanized Pipes Sticking Out of The Ground?
If you notice two mysterious galvanized pipes sticking out of the ground, it could be a sign of something bigger below the ground. That’s because although electricity and natural gas power many furnaces today, 1970s homes had fuel-oil powered furnaces. This came with an underground fuel oil tank. Evidence of that reveals in the pair of galvanized pipes sticking out often within a couple of feet of each other.
Why Is There a Radon Pipe in My Basement?
Homes with basements are often suspected of having higher radon levels. That’s because the porous foundation walls allow the gas to enter the house. Besides, basements contain a sump well and other numerous access points from which radon can enter a home.
New houses usually have passive mitigation systems installed (that’s often a 4-inch pipe from below the basement slab to the exterior). However, the radon pipe has limited effectiveness as there isn’t enough stack pressure to draw up the radon gas from the soil.
Fortunately, today the pipes can be adapted to include a fan that draws air if the radon levels in the house are too high. Other ways recommended in lowering radon levels include ensuring the integrity of the basement slab and covering sump pits, and closing openings around water piping and sewer.
What To Do with The Mysterious Pipes in the Basement Floor?
If your basement floor has exposed rusted unknown pipes, grab a can of paint that complements or matches the basement. Give each pipeline a couple of coats. You’ll have cleaned up the unsightly pipes, making the space feel more cohesive.
Some people are often lured into cutting or flushing the pipes or even adding concrete. However, this isn’t advisable as you may not know exactly the purpose for the pipeline. So, instead, consult a plumbing professional before making such a decision.
Sources:
https://diy.stackexchange.com/questions/74247/mystery-pipes-in-basement-where-do-they-go
